MAF sensor question

[Dan414]

Hey Guys,

I have a 2001 Beetle TDI and have had the classic symptoms of MAF sensor problems about 6 months ago – lack of acceleration, topping out at 2800 or 3000 rpm, loss of speed with cruise control, etc. So I disconnected the MAF and it ran like new – got a new one put it on with silicone dielectric grease and everything was fine – for a few months until I noticed that the symptoms had gradually come back including loss of around 10% MPG. Unplugged it and it runs great.
Reapplied grease and cleaned it with MAF sensor cleaner, but very little if any improvement. I’m guessing that I got a bad one. Oh, well.

So my question is this: Until I get the new one, is it a bad thing to leave it unplugged? Other than the fact that I’m not getting maximum efficiency – it’s not working anyway – is there any harm being done by driving it unplugged? I haven’t seen where anyone has commented on that issue in the forum.

Thanks for your help!

Dan

[Vincent Waldon]

Running without a MAF isn't dangerous... the car will not get great mileage or performance and the check engine light that comes on may obscure a different issue if one crops up.

As an aside, you're not running an aftermarket oiled filter (K&N, etc) by any chance?

[Dan414]

I just changed the air filter for a Mann C 37 153. I looked at the old one I pulled out and it's a NAPA Gold 2472. Is that a good one? Thanks....

[Vincent Waldon]

Yup... all good.  I asked about oiled filters because they are known to be hard on MAFs if over-oiled... here's hoping you simply got a bad MAF.

When you get your new one you might want to ensure it's the new design:  Bosch 0 281 002 757 (as opposed to the old version Bosch 0 280 217 121)....Bosch has evidently made  improvements to the design that make this the one to grab, but some suppliers are still selling off their old stock.